This invention relates to novel rodenticides, methods of killing rodents and methods of manufacturing novel rodenticides.
Rodents have long been considered to pose a significant problem to human health, property and crops. The rat, alone, is known to carry nearly 70 diseases, many of which are transmittable to humans, including bubonic plague, typhus and leptospirosis. Meanwhile, farmers struggle to protect their crops from rodents and it has been estimated that probably 10% of the world's food supply is consumed or damaged by rats.
Governments in developed and developing countries are concerned that the risk from rodents has increased significantly in recent years given the recent rodent population explosion, working on the premise that an increased number of rodents means an increased risk to humans from such rodents. The rodent population explosion is thought to be the culmination of various factors such as the increasing number of mild and wet winters, the increasing availability of food litter in towns, and the increasing incidences of rodent resistance to known rodenticides.
The need for new rodenticides and methods of killing rodents, therefore, has never been greater. The present invention provides a new class of rodenticides.
Known rodenticides tend to be classified either as acute or chronic based on their mode of action. The chronic type, commonly known as anticoagulants, dominates the pest control market with approximately 95% of all rodenticides used belonging to this group. Warfarin is such an anticoagulant.
Rodent resistance to anticoagulants is increasing. As a result, other rodenticides are having to be used to control these resistant “super-rats”. The drawback of many of these alternative rodenticides is that they tend to be potent not only to rodents, but also to non-target species such as pets, livestock and even humans. The most potent second-generation anticoagulants, for example, may only be used inside buildings so as to limit exposure of non-target animals. Two non-anticoagulant rodenticides are also available but guidelines limit repeat applications to 6 monthly intervals. The present invention provides a new class of rodenticide that is able to kill rodents and which is particularly advantageous as it is effective against rats that are resistant to currently available rodenticides. Also, the new rodenticides according to this invention are non-toxic to humans, various pets and livestock thus reducing the risk of environmental harm as well as avoiding harm to those humans in frequent contact with the rodenticide such as workers in the pest control industry.
Other attempts to design a new generation of rodenticide include WO 2006/095128, which teaches a rodenticide comprising an antibody or an antibody fragment thereof that binds to an extracellular epitope of a protein expressed in a rodent. The described method is complex because the user has to first identify a candidate epitope before the antibody which is going to become part of the rodenticide can be made. Having made the antibody, the antibody then needs to be tested for efficacy. The user then needs to decide which fusion to attach to the antibody, for example, the antibody can be fused to a toxin or a contraceptive. Finally, the fusions are administered to the rodent, where hopefully, the antibody part of the fusion can target the whole molecule to the appropriate place in the rodent.
The present invention does not require the step of having to make an antibody or an antibody fragment. The present invention does not even require the user to have to identify an epitope of a protein expressed in a rodent. The present invention therefore provides a far simpler method of producing a rodenticide. The present invention does not relate to an epitope that is expressed in a rodent. Instead, it relates to a toxin that is not natively found in a rodent because it is found in Yersinia pestis. 